Through the action of the sense organs, the individual is made aware of himself and his world.

His experience is based in the first instance upon a fourfold process:
1. A Stimulus affects a nerve structure.
2. The impulse contacts and activates a sense organ (receptor organ, such as the eye).
3. The impulses aroused in the sense organ travel to the brain.
4. One or more structures in the brain interpret the impulse as a feeling or sensation.

It is common for mental activity to decline as a person gets older. This does not mean that there is no way of preventing the decline, but there are ways in which a person can keep his/her brain in shape. Here are a few ways that you could try to prevent your brain cells from dying at a faster rate than expected:

This article discusses the possibility that the real work of the brain is done while we sleep. It has been said, that we cannot die, from lack of sleep because we would first of died from lack of dreams. How important are our dreams? Why is it that our dreams are so important?